# thirdparty_extract

**Repository Path**: mirrors_GerHobbelt/thirdparty_extract

## Basic Information

- **Project Name**: thirdparty_extract
- **Description**: clone of Artifex mupdf extract library: git://git.ghostscript.com/extract.git
- **Primary Language**: Unknown
- **License**: GPL-3.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-10-13
- **Last Updated**: 2026-05-30

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# thirdparty/extract

Clone of Artifex' `extract` library at git://git.ghostscript.com/extract.git.

## References / Origin:

- Artifex @ github: https://github.com/ArtifexSoftware/extract
- original `extract` repo: https://git.ghostscript.com/?p=extract.git;a=summary
- original `extract` repo duplicate: https://git.ghostscript.com/?p=thirdparty-extract.git;a=summary

----


## Directory tree:

-    `Makefile`        :: Builds and runs tests.
-    `include/`        :: Public API.
-    `src/`            :: Scripts, C implementation and internal headers.
     -   `build/`      :: Generated object files, executables etc.
-    `test/`           :: Test files.
     -   `generated/`  :: Files generated by tests.



## Suggested setup for testing:

Checkout ghostpdl and mupdf into the same directory.

Inside ghostpdl:

	ln -s ../mupdf/thirdparty/extract extract

Then either:

- Inside ghostpdl:
 
  ```
  ./autogen.sh --with-extract-dir=extract
  make -j 8 debug DEBUGDIRPREFIX=debug-extract-
  ```
    
- Inside mupdf:
 
  ```
  make -j 8 debug
  ```

  or:
  
  ```
  make test-rebuild-dependent-binaries (for the first time)
  make test-build-dependent-binaries (for incremental builds)
  ```


Then build and run tests from inside mupdf/thirdparty/extract
as below.

Build and run tests with:

    make



## Conventions:

###  Errors:
    
Functions return zero on success or -1 with errno set.


###  Identifier/symbol names:

All identifiers that can be seen by client code (generally things
defined in include/) start with 'extract_'.

Similarly global symbols in generated .o files all start with
'extract_'; this is tested by target 'test-obj'.

Other identifiers and symbols do not have an 'extract_' prefix - not
necessary because client code cannot see these names.

Header names in include/ start with 'extract_'.


###  Allocation:

Functions that free a data structure generally take a double pointer
so that they can set the pointer to NULL before returning, which helps
avoid stray invalid non-NULL pointers. E.g.:

    extract_span_free(extract_alloc_t* alloc, span_t** pspan);
    /* Frees a span_t, returning with *pspan set to NULL. */

This double-pointer approach is also used for raw allocation - see
include/extract_alloc.h.


###  Lists:

Lists of data items are generally implemented using an array of
pointers and an int 'foo_num' entry, e.g.:

    line_t**    lines;
    int         lines_num;